1. Field of the Invention
The present invention relates to a surveying instrument, a surveying instrument having a collimation telescope with a focusing apparatus, a surveying instrument having a power focus mechanism, and a surveying instrument having a multiple-focus apparatus.
2. Description of the Related Art
In a conventional surveying instrument, such as a total station, a focusing lens of a collimation telescope is manually moved to control the focus. In recent years, attempts have been made to provide an AF (automatic focusing) apparatus on the collimation telescope.
The surveying instrument having an AF apparatus basically includes a focus detector for detecting the focus through the collimation telescope, and a controller for controlling the movement of the focusing lens of the collimation telescope to a focal point in accordance with the focus state detected by the focus detector. If an AF switch is turned ON while viewing an object to be measured through the collimation telescope, the focusing lens is moved to the focal point of the sighting object. There is no problem with the focusing operation when the relative position of the collimation telescope and the sighting object is fixed.
In a pile driving operation, when the position of the sighting object, such as a target member, is moved to a specific distance position (e.g., 5 m, 10 m, etc.), the position is detected, i.e., the measurements are carried out, while the sighting object is being moved. However, to carry out the focusing operation upon the measurement, it is necessary for an operator to frequently and repeatedly turn the AF switch ON, so that the operation efficiency is very low.
In addition, at a measurement site, an operator may want to move the focusing lens without using the AF mechanism, for example when the AF function does not work well due to, for example, noise when the focusing lens must be moved at high speed or when a fine focus adjustment is carried out. Even in such a case, however, in a conventional surveying instrument, the operator can only move the focusing lens by manually rotating a manual adjustment ring in an MF (manual focusing) operation or by operating the AF mechanism.
It is an object of the present invention to eliminate the above-mentioned drawbacks of the surveying instrument having an AF function in the prior art by providing a surveying instrument, a surveying instrument having an AF function, a surveying instrument having a PF function, and a surveying instrument having a multiple-focus function, in which the focusing operation can be carried out in various fashions, for example, the AF operation can be easily carried out not only for the measurement of an object which is not moved, but also for the measurement of an object which is moved in a pile driving operation, or alternatively, the focusing operation can be carried out by being driven electrically.
In order to achieve the above-mention object, a surveying instrument having an AF apparatus is provided, which has a focusing lens and a collimation telescope. The surveying instrument includes a focus detector for detecting a focus state through the collimation telescope, and a controller for moving the focusing lens of the collimation telescope to a focal position, based on the focus state detected by the focus detector. The surveying instrument includes a single focus mode at which only one detection of the output of the focus detector and only one control operation of the controller based on the detected output are carried out, and a continuous focus mode at which a plurality of detections of the output of the focus detector and a plurality of control operations of the controller based on the detected outputs are sequentially carried out, the single focus mode and the continuous mode being selectively performed.
In an embodiment, the single focus mode is performed when an AF switch is turned ON only once, and the continuous focus mode is performed when the AF switch is turned ON twice within a predetermined time.
In an embodiment, the single focus mode is performed when an AF switch is turned ON only once, and the continuous focus mode is performed when the AF switch is turned ON continuously during a predetermined period of time.
In an embodiment, the surveying instrument further includes a mode selection switch, separate from the AF switch, which is adapted to select either the single focus mode or the continuous focus mode.
In an embodiment, the controller moves the focusing lens of the collimation telescope to a focal position corresponding to a specific default distance when the output of the focus detector detects an out-of-focus state after the controller operates.
Preferably, a default distance setting device is provided for optionally setting the default distance.
In an embodiment, the continuous focus function is stopped upon a timer lapsing.
In an embodiment, the power source of the AF apparatus is turned ON by the operation of the AF switch.
According to another aspect of the present invention, a surveying instrument having a power focus mechanism is provided, having a focusing lens and a collimation telescope, including a motor drive mechanism having an electric motor for driving the focusing lens in an optical axis direction; and a power focus mechanism which drives the focusing lens of the collimation telescope one of forwardly and rearwardly in the optical axis direction via the motor drive mechanism.
In an embodiment, a lens barrel of the collimation telescope is reversibly rotatable about a horizontal axis between a normal measurement position and a reverse measurement position, and the collimation telescope is provided on an eyepiece side of the lens barrel with a pair of PF switch knobs that are located above and below a horizontal plane passing through an optical axis of an eyepiece, at the normal measurement position and the reverse measurement position of the lens barrel of the collimation telescope.
In an embodiment, the moving speed of the focusing lens increases as the displacement of a switch knob of the pair of PF switch knobs is increased in one of the forward and rearward direction from a neutral position, wherein in the case where the switch knob is operated so as to reach a movement extremity thereof, the moving speed of the focusing lens increases as the stop time of the switch knob at the movement extremity increases.
Preferably, an MF mechanism is further included, which is adapted to manually drive the focusing lens of the collimation telescope in the optical axis direction.
Preferably, the MF mechanism is provided on a reversibly rotatable lens barrel of the collimation telescope, the MF mechanism including a manual adjustment ring exposed toward the eyepiece side of the lens barrel, the adjustment ring surrounding an eyepiece, provided on the lens barrel, when viewed from the eyepiece side in the optical axis direction, and the manual adjustment ring being located in front of the eyepiece, wherein the focusing lens can be moved in the optical axis direction by the rotation of the manual adjustment ring.
Preferably, the directions of rotation of the manual adjustment ring to advance and retract the focusing lens correspond to movement directions of the PF switch knobs to advance and retract the focusing lens, respectively.
In an embodiment, the PF switch knobs are located within the contour of the manual adjustment ring when viewed from the eyepiece side in the optical axis direction thereof.
In an embodiment, the PF switch knobs are located outside of the contour of the manual adjustment ring when viewed from the eyepiece side in the optical axis direction thereof.
In an embodiment, the manual adjustment ring is directly connected to the power focus mechanism which drives the focusing lens.
According to another aspect of the present invention, a surveying instrument having a multi-focus apparatus is provided, which has a focusing lens and a collimation telescope, including a motor drive mechanism having an electric motor which reciprocally drives the focusing lens in the optical axis direction; a focus detector for detecting the focus state of the collimation telescope; an AF controller for moving the focusing lens of the collimation telescope to a focal position through the motor drive mechanism, based on the focus state detected by the detection device; and a power focus mechanism which electrically drives the focusing lens of the collimation telescope through the motor drive mechanism in the optical axis direction, independently of the output of the focus detector.
In an embodiment, a lens barrel of the collimation telescope is reversibly rotatable about a horizontal axis between a normal measurement position and a reverse measurement position, wherein the collimation telescope is provided on an eyepiece side of the lens barrel with a pair of PF switch knobs that are located above and below a horizontal plane passing through an optical axis of an eyepiece, at the normal measurement position and the reverse measurement position of the lens barrel of the collimation telescope, respectively.
In an embodiment, the pair of PF switch knobs are each provided with a finger engagement concave portion that is curved inward toward the center of the lens barrel of the collimation telescope, so that one of a forward and reverse movement of the finger engagement concave portion from a neutral position gives an operation signal to the motor drive mechanism to move the focusing lens in a corresponding one of a forward and rearward direction.
In an embodiment, the moving speed of the focusing lens increases as the displacement of a switch knob of the pair of PF switch knobs is increased in one of a forward and rearward direction from a neutral position, wherein in the case where the switch knob is operated so as to reach a movement extremity thereof, the moving speed of the focusing lens increases as the stop time of the switch knob at the movement extremity increases.
Preferably, the lens barrel is provided on the eyepiece side thereof with an AF switch, between the pair of PF switch knobs, wherein the AF switch is used to operate the AF controller.
In an embodiment, the center of the eyepiece is deviated in the horizontal direction from the center of the collimation telescope, the AF switch being located on the lens barrel next to the eyepiece.
In an embodiment, an MF mechanism is further included for manually moving the focusing lens of the collimation telescope in the optical axis direction.
In an embodiment, an MF mechanism is further included which is provided, on a reversibly rotatable lens barrel of the collimation telescope, with a manual adjustment ring exposed toward the eyepiece side of the lens barrel, the adjustment ring surrounding an eyepiece, provided on the lens barrel, when viewed from the eyepiece side from the optical axis direction, and the manual adjustment ring being located in front of the eyepiece, wherein the focusing lens can be moved in the optical axis direction by the rotation of the manual adjustment ring.
Preferably, the directions of rotation of the manual adjustment ring to advance and retract the focusing lens correspond to movement directions of the PF switch knobs to advance and retract the focusing lens, respectively.
In an embodiment, the PF switch knobs are located within the contour of the manual adjustment ring when viewed from the eyepiece side in the optical axis direction thereof.
In an embodiment, the PF switch knobs are located outside of the contour of the manual adjustment ring when viewed from the eyepiece side in the optical axis direction thereof.
Preferably, the manual adjustment ring is directly connected to the power focus mechanism.
The present disclosure relates to subject matter contained in Japanese Patent Applications No. 2000-139516 (filed on May 12, 2000), No. 2000-140650 (filed on May 12, 2000), and No. 2000-140651 (filed on May 12, 2000), which are expressly incorporated herein by reference in their entireties.
The present invention will be described below in detail with reference to the accompanying drawings in which:
FIG. 1 is a systematic connection diagram of a surveying instrument having an AF apparatus according to a first embodiment of the present invention;
FIG. 2 is a conceptual view of a focus detector (AF unit, phase difference type focus detector), as viewed in the direction of an arrow II in FIG. 1;
FIG. 3 is a schematic view showing a positional relationship among a pair of pupil areas on an objective lens of a focus detector, a reflection mirror, and a light receiving fiber, as viewed from the direction of the arrows IIIxe2x80x94III in FIG. 1;
FIG. 4 is a flow chart of the AF operation by a control circuit;
FIG. 5 is a flow chart of the focusing operation shown in FIG. 4;
FIG. 6 is a perspective view of a collimation telescope of a total station, viewed from the eyepiece side, according to a second embodiment of the present invention;
FIG. 7 is a perspective view of a collimation telescope of a total station shown in FIG. 6, viewed from the objective lens side;
FIG. 8 is a front elevational view of an eyepiece portion shown in FIG. 7;
FIG. 9 is a right side elevational view of FIG. 8;
FIG. 10 s a plan view of FIG. 8;
FIG. 11 is a systematic connection diagram of a collimation telescope of a surveying instrument according to a second embodiment of the present invention;
FIG. 12 is a perspective view of an example of a drive mechanism of a focusing lens in a collimation telescope according to a second embodiment of the present invention;
FIG. 13 is a flow chart of the operations of a surveying instrument according to a second embodiment of the present invention, by way of example;
FIG. 14 front elevational view of an eyepiece portion according to a third embodiment;
FIG. 15 is a right side view of FIG. 14;
FIG. 16 is a perspective view of a collimation telescope of a total station, viewed from the eyepiece lens side, according to a fourth embodiment of the present invention;
FIG. 17 is a front elevational view of an eyepiece portion of a collimation telescope shown in FIG. 16;
FIG. 18 is a systematic connection diagram of a collimation telescope of a surveying instrument according to a fourth embodiment of the present invention;
FIG. 19 is a schematic view of a pair of pupil areas on an objective lens of a focus detector, as viewed from the direction of the arrows XIXxe2x80x94XIX in FIG. 18;
FIG. 20 is a flow chart of the operations of a surveying instrument according to a fourth embodiment of the present invention, by way of example; and
FIG. 21 is a front elevational view of an eyepiece portion in a surveying instrument according to a fifth embodiment of the present invention.